In a large pot, heat the olive oil over medium heat. Add the leeks and carrots, and sauté until tender, 5 to 6 minutes. Set aside 1 cup corn for garnish; add the remaining corn to the pot and continue to cook until all the vegetables are very soft and tender, 2 to 3 minutes more.

Add the wine to the pot and bring to a simmer. Cook until the liquid is almost completely reduced, 7 to 9 minutes. Add the broth and bring the mixture to a simmer.

Season the soup with cumin, bay leaf, cayenne pepper, kosher salt and black pepper. Continue simmering until the soup has developed a good flavor, 30 to 40 minutes.

Puree the soup using an immersion blender (or you can use a regular blender or food processor) until it’s smooth. For an extra-silky effect, strain the pureed soup through a fine-mesh sieve. Taste the soup and season again with salt and pepper as desired. If using, stir in the heavy cream and return the soup to a simmer.

In a small pan, heat the butter over medium heat. Add the reserved 1 cup corn kernels and sauté until tender and lightly golden, 3 to 5 minutes.

To serve, ladle the soup into bowls and garnish with 2 tablespoons corn kernels, 1 tablespoon chopped basil and a pinch of cayenne pepper. Serve immediately.